Troubleshooting Trailer Brakes That Engage with Direct 12V Power But Not with Brake Controller

Question

Question:

I just put new brakes on my trailer when I apply the brake controller I can hear the brakes hum but theyre not engaging Ive adjusted them up so that they slightly drag they still dont engage if I hook a jump box directly to the brakes they lock up I put a test light on the power wire at the brakes and had someone adjust the power setting on my brake controller and the test light got bright and dim so I know that the brake controllers working

asked by: Floyd G

0

Expert Reply:

Thank you for the details on your testing of your new trailer brakes # AKEBRK-35.

Your successful jump box test direct to the brake circuit on the trailer's 7-way plug tells us the trailer side of things is working (since the brakes will lock up with that full power input) so this suggests the problem is on the vehicle side. The brake pressure should be adjusted so that when you spin a wheel by hand you do feel some resistance.

If you happened to test each individual brake, rather than going through the 7-way plug, then it is still possible there could be a problem in that part of the trailer wiring, but if you tested at the 7-way trailer plug it is safe to conclude the trailer is ok.

I suggest using a voltmeter like # PT89ZR at your vehicle 7-way socket. Set the controller for maximum power and maximum boost and have a helper press the manual control while you apply the meter probe to the brake circuit contact at the 5:00 position. With full power and full boost your meter should read close to 12.8V. If not then you probably have corrosion within the 7-way or damaged wiring leading to it.

You can repeat the same voltmeter test right at the back of the controller. This will potentially save you the time and effort of troubleshooting the vehicle wiring.

Cut the blue wire a few inches from the controller so you can re-connect it after the test. Apply the meter to the output wire in the same way you did at the 7-way. If you get full power at the controller's output wire then you know the issue is in the wiring between the controller and the 7-way socket. If you still don't get full power then the controller is damaged internally.

expert reply by: Adam R

0

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Answer 1

The best place to locate a brake controller is, like you said, out of the way, but also in a spot that is easy for you to activate the manual override switch in case of an emergency situation. Most people mount the controller on the underside of the…

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Answer 2

You are correct, you should only be getting output when the brake is applied, or the override switch is activated. It sounds like the controller might be bad, but to make sure, you should probably bench test it before tossing it. Use a circuit…

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Answer 3

On a 2017 Toyota Tacoma the location to install the #3031-P is behind the kick panel to the left of your left foot. I attached a picture. You'll need to pull off the kick panel.

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Answer 4

Your brake controller should be getting 12 volts of power going into the brake controller. The wire that feeds power to the brake controller is the Black wire. You can test this wire by using a multimeter part #PT89ZR. The amount of power coming out…

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Answer 5

Your trailer brakes will still work with the assemblies mounted upside down where the magnet is above the spindle, but from the customers we know who have done this we have found that the stopping power won't be as strong as if they were mounted…

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Answer 6

To wire your electric brakes you will want to run 10 gauge wire #10-1-1 to one of the brakes and run it to the other brake, using butt connectors like #05732-2 to connect them. The grounds will not be spliced, each brake assembly should have its own…

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Answer 7

What type of brake controller do you have? Is it a proportional or time delayed? Also, are you using the brake pedal or the manual override? If you have a proportional brake controller and you are using the manual override then you should see a full…

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Answer 8

The braking performance will not be very good if you install brake assemblies on the wrong side of the trailer. The left side assembly is the driver's side (if the trailer were a car) and the right side is the passenger's side. The actuating…

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Answer 9

Since the trailer was off of the ground it would not take much voltage to stop the wheels from spinning so they may be getting power but they may not be getting enough power due to a short or wiring issue. But 9 times out of 10 weak trailer brakes…

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Answer 10

There are many things that can affect the voltage on the brake output wire from your brake controller to your trailer brakes such as the power setting on your brake controller, how you are testing the wire and if you are testing it with the brakes or…

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Answer 11

No problem, we can get this sorted out. The first thing I want you to look at are the centers of the axles. Round trailer axles have a bow in them so the centers of the axles should be higher than the ends. When weight is put on them they straighten…

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Answer 12

The Dexter Electric Brake Kit w/ Cast Backing - Self-Adjusting - 12-1/4" - Left/Right Hand - 15K #23-446-447 will fit any 15K axle that have the standard 7 bolt mounting flange. These are self-adjusting brakes so there is no need for manual…

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Troubleshooting Trailer Brakes That Engage with Direct 12V Power But Not with Brake Controller

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